Six dead in rare US drone strike outside Pakistan tribal areas

A US drone killed six people in northwest Pakistan Thursday in only the second such strike outside the country's lawless tribal districts, threatening to inflame tensions between Washington and Islamabad.

The missile attack targeted a religious seminary that security officials said belonged to the Haqqani network -- blamed for some of the deadliest attacks in neighbouring Afghanistan -- in the Hangu district of Khyber Pakhtunkhwa province.

Earlier this month the network's chief financier Nasirudddin Haqqani was gunned down in mysterious circumstances in a village on the edge of Islamabad.

Thursday's drone strike was the first in the country since Pakistani Taliban chief Hakimullah Mehsud was killed in a similar attack in the North Waziristan tribal district on November 1.

That attack prompted a furious response from Pakistan, with the interior minister accusing Washington of sabotaging fledgling peace efforts with the Taliban and opposition parties calling for a blockade of NATO supply lines to Afghanistan.

Two local security officials identified two of the dead as Mufti Ahmad Jan and Mufti Hameedullah and said they were both members of the Haqqani network.

"The seminary belonged to one Qari Noor Muhammad, a previously unknown figure. It was not clear if he was present in the seminary at the time of attack", an official said.

Washington has long demanded that Pakistan take action against the Haqqanis, who are blamed for numerous bloody attacks in Afghanistan including one on the US embassy in Kabul in 2011.

US officials have in the past accused Pakistani intelligence agencies of links to the Haqqani network, which has bases in the tribal districts.

Since 2004 the United States has carried out hundreds of missile attacks from unmanned aircraft on suspected militants linked to the Taliban and Al-Qaeda.

The vast majority of them have hit targets in the seven tribal areas bordering Afghanistan, which have a separate legal and political governance system from the rest of the country.

Thursday was the first time a US drone hit a district inside Khyber Pakhtunkhwa. The only previous strike outside the tribal areas came in Bannu district, a so-called "frontier region".

The number and identity of casualties is often hard to determine because the tribal areas are off-limits to foreign journalists and aid organisations, but the London-based Bureau of Investigative Journalism estimates deaths at between 2,500 and 3,700.

Hundreds of civilians have died in the attacks, according to various estimates, prompting outrage in Pakistan and abroad.

A major report last month from rights campaigners Amnesty International said the US may be guilty of war crimes.

The Pakistani government officially condemns drone strikes as a violation of its sovereignty, and last month Sharif urged US President Barack Obama to halt the programme during a meeting in Washington.

Despite their deep unpopularity in Pakistan, the US sees them as a vital tool in the fight against militants in the tribal areas.